In industrial production, ovens and dryers play a central role in the processing of a variety of materials. They are essential in processes in which products are dried, hardened or changed in their structure and chemical composition. To ensure safety and optimize the efficiency of these thermal processes, precise flow monitoring is essential. flow monitoring is of crucial importance. This applies in particular to the European standard EN 1539.
EN 1539:2015 "Drying installations for flammable substances - Fire safety requirements" deals with safety aspects in the drying of flammable materials. It specifies which measures must be taken to minimize the risk of ignition of the materials. Flow monitoring is an elementary component of these measures: It ensures that the risk of an uncontrolled explosion or fire is reduced to an absolute minimum.
The risk: explosion and fire
Flammable materials that are processed in ovens and dryers can form explosive mixtures with the air under certain circumstances. This risk of explosion increases with the drying speed and the amount of material being processed. An effective safety concept must include preventive measures against the possible formation of ignition sources and against the accumulation of flammable gases or dusts.
The role of flow monitoring
Flow monitoring plays a dual role: on the one hand, it ensures an even distribution of the required drying air and, on the other, it serves as an early warning system in the event of a disruption to the air flow. Both serve to prevent dangerous situations.
Insufficient airflow can cause combustible gases and vapors to accumulate and create an explosive mixture. Conversely, too strong an airflow can dry out materials and thus promote the formation of combustible dust. Monitoring the air flow ensures that the air flow used is within the safe operating parameters.
Technical implementation of flow monitoring and energy-efficient control
Calorimetric sensors are often used for flow monitoring. These sensors use the principle of heat transfer from a heated element to the flow and can therefore detect changes in the air flow. State-of-the-art sensors offer high precision and react quickly to fluctuations in the flow, which is essential for compliance with the EN 1539 standard. In addition, the high functional safety requirements (Safety Integrity Level 2 or Performance Level d) must be met.
Especially for this application we at SEIKOM Electronic have developed various devices especially for this application:
- SIL2-compliant monitoring of the supply air with4-20 mA analog signal and integrated switching point monitoring via relay output: NLSW®45-3 SIL2 Analog in conjunction with 2 sensors F3.x SIL2
- SIL2-compliant monitoring of exhaust air suitable for environments up to 250°C: NLSW®45-6SIL2 in conjunction with F8.x SIL2 sensors - optionally available for environments up to 400°C
- Reliable energy-optimized control of the kiln or drying system with the RLSW®8 volumetric flow meter suitable for environments up to 350°C with linear analogue signal, ideal for further processing in the PLC
Monitoring systems and alarms
In addition to measuring the flow velocity, such a monitoring system also includes components for signal processing and alarming. In the event of deviations from the specified limit values, the systems automatically trigger alarms and can initiate countermeasures in conjunction with the control technology - for example, switching off heat sources or activating extinguishing systems.
Compliance with EN 1539 implies that flow monitoring must not be viewed in isolation, but as part of an integrated safety concept. This concept includes regular inspections and maintenance as well as a risk assessment that also takes into account the potential hazards in the event of a system failure.
Another important aspect of fire safety is the training of operating personnel. Employees must be able to understand the function and importance of flow monitoring and react correctly if necessary. This also includes knowledge of the basic requirements of EN 1539 and the company-specific safety protocols.
Conclusion
Flow monitoring is a critical factor for the safe execution of drying processes with flammable materials. It makes a significant contribution to minimizing the risk of fires and explosions and thus ensuring compliance with the EN 1539 standard. The use of high-quality monitoring systems and qualified training of operating personnel can significantly improve both the safety and efficiency of industrial ovens and dryers.
For further information on the optimum implementation of flow monitoring systems and compliance with the requirements of EN 1539 in your company, please contact us directly. SEIKOM Electronic is always at your side with expertise and individual solutions.
